On February 3, 2000, about 0800 Eastern Standard Time, a Boeing 737-300, N397US, encountered turbulence after departure from General Edward Lawrence Logan International Airport, Boston, Massachusetts. There was no damage to the airplane, which was owned and operated by US Airways as flight 6509. There were no injuries to 4 crewmembers and 55 passengers, while 1 crewmember was seriously injured. Visual meteorological conditions prevailed for the flight destined for Ronald Regan Washington National Airport, Washington, DC. An instrument flight rules flight plan was filed for the air carrier flight conducted under 14 CFR part 121. The manager of Flight Safety at US Airways stated: "The flight was dispatched with MEL No. 22-3, yaw damper inop. After level off and during initial passenger service the flight began to encounter turbulence that became progressively worse. The flight attendant returned the serving cart to its stowage bin and then strapped into her jumpseat. During the continued turbulence the cart began to break free. On instinct the flight attendant put up her foot to hold the cart; however, it pushed her foot backwards. At first, the flight attendant assumed her foot was just bruised and would get better on its own, it did not. She visited her own doctor who diagnosed that she had fractured the 5th metatarsal base of her left foot."